Abstract: Objective To investigate the trend changes and influencing factors of spring allergic conjunctivitis in ophthalmic emergency in 2019-2021. Design Retrospective cases series. Participants 1985 patients with acute allergic conjunctivitis in the ophthalmic emergency department of Beijing Tongren Hospital in March 2019, and 912 and 2343 patients with acute allergic conjunctivitis in the same period of 2020 and 2021. Method Date was extracted from hospital information system, including ages, genders, diagnoses and number of patients. The air quality index and pollen concentration index were analyzed with daily allergic conjunctivitis patient number. Patients were divided into juvenile group (0-17 years old), youth group (18-45 years old), middle-aged group (46-64 years old) and elderly group (≥ 65 years old). Main Outcome Measures Ages, number of patients, air quality index and pollen concentration index. Result In March 2019, 2020, 2021, there were 1985 cases (34.5%), 912 cases (29.9%) and 2343 cases (39.7%) of allergic conjunctivitis patients. In March 2019, there were 541 (27.2%), 1083 (54.6%), 301 (15.2%) and 60 (3.0%) cases in juvenile group, youth group, middle-aged group and elderly group, respectively. In March 2020, there were 125 (13.7%), 562 (61.6%), 177 (19.4%) and 48 (5.2%) cases, respectively. In March 2021, there were 549 (29.4%), 1266 (54.0%), 251 (13.4%) and 73 (3.1%) cases, respectively. In March 2019, 2020 and 2021, there was no correlation between the number of allergic conjunctivitis patients and the air quality index (r=0.186, 0.111, 0.172, all P>0.05). In March 2021, the number of allergic conjunctivitis patients was highly correlated with the pollen concentration index (r=0.908, P＜0.001). Conclusion Influenced by the COVID-19 epidemic and home isolation, the number of ophthalmic emergency visits of allergic conjunctivitis in March 2020 was decreased 1/2. Moreover the number of juvenile groups visits were decreased 3/4 in March 2020 compared with in March 2019. Rising pollen concentrations increased the incidence of allergic conjunctivitis in Beijing in March 2021. (Ophthalmol CHN, 2021, 30: 369-373)

Key words: ophthalmic emergency, allergic conjunctivitis, COVID-19